In residential and commercial building structures, it is common practice to insulate ceilings by blowing loose cellulose material into the attic space so that it covers the ceiling from above. The loose cellulose insulation is normally blown in to a height of ten to sixteen inches, which exceeds the height of the four or six inch ceiling joists. Since attics have hatches, scuttles or pull-down stair or ladder openings of various sizes to gain access to the attic, the additional loose insulating material would fall through the openings unless contained by a barrier or dam.
To overcome this problem, cardboard dams have been cut to size and stapled to the hatch opening on the outside of the frame. This is the least expensive dam but is very flimsy and the four corners of the hatch opening are not secure. There is also a void space around the entire two inch by four inch or two inch by six inch frame that is not covered by insulation. This results in heat escaping.
Custom-built wood or plywood dams have also been used on top of the frame of the openings to raise the height and form a barrier dam for the insulating material. However, this method to fabricate and install the wood dam is time-consuming and, therefore, costly. There are a number of other hatch dam products sold on the market that will contain or dam the insulating material, but these are made from steel or plastic materials that are only available in specific sizes and are quite costly. As a result, they are not particularly favorable since hatches may come in many sizes.